Latest ArticlesCarbohydrate antigen 19-9 (CA19-9) with multi epitopes relatively high expresses on colorectal cancer (CRC) cells, making it an attractive target for developing radioimmunotherapy (RIT) for CRC. The lutetium-177 (177Lu) labeled monoclonal antibodies (mAbs) can selectively bind the corresponding antigens and release targeted cytotoxic radiation, which could induce cell apoptosis and reduce the drug-induced resistance. Here, a series of CA19-9 mAbs were labeled with zirconium-89 (89Zr), and one with high tumor uptake was screened via PET imaging, which has potential application for the diagnosis of CRC. Then the screened mAb (C003) labeled with 177Lu was utilized for CA19-9 targeted RIT, which presents a significant suppression effect on the growth of colo205 xenografts than immunotherapy alone. Meanwhile, the side effects of 177Lu-DOTA-C003 are limited according to the results of in vivo study. Both 89Zr-DFO-C003 for CRC immune-PET imaging and 177Lu-DOTA-C003 for RIT against CRC exhibit good potential in clinical applications.
Two tetravalent uranium silicate and germanate M2UIVT3O9 (M = K, Cs; T = Si, Ge) crystals were crystalized under inert gas by molten salt flux growth method. K2USi3O9 (1) crystallizes in the monoclinic space group P121/n1 with lattice parameters a = 7.1076 Å, b = 10.4776 Å, c = 12.2957 Å, γ = 120° and V = 915.67 Å3. Cs2UGe3O9 (2) crystallizes in a hexagonal space group P-6 with lattice constants of a = 7.5138 Å, b = 7.5138 Å, c = 11.0114 Å, γ = 120° and V = 538.38 Å3. Bond valence calculations indicate tetravalent uranium in both structures, which contain three-membered single-ring T3O96− trimers. K2USi3O9 is the first uranium silicate that contains the Si3O96− trimers.
Nitrogen enrichment and increased nitrogen content is an effective strategy for enhancing adsorption of uranium by carbon nitride polymers. Herein, we reported the uranium absorption by using a structurally well-defined and nitrogen-rich carbon nitride polymer with C3N5 stoichiometry for the first time. In comparison with the adsorption performance of g-C3N4 for U(VI), the conjugation system of the material was increased by connecting the heptazine unit through the azo bridge in the structure of C3N5, so that C3N5 exhibited several times higher adsorption performance than that of g-C3N4. The C3N5 has high kinetics for uranyl ions, which can adsorb 100 mg/g U(VI) in only 10 min and reach complete adsorption equilibrium in 60 min; the theoretical maximum adsorption capacity is 207 mg/g, meanwhile, the material exhibits high selectivity. The results of spectral analysis and theoretical calculations indicate that the process of uranyl ion capture by C3N5 is a combination of physical and chemical adsorption, and its higher density of electronic states makes the electrostatic binding ability enhanced, which is favorable to the adsorption of uranyl ions by C3N5. This work indicates that C3N5 has great promise and application in the separation and enrichment of uranyl ions, and also provides a reference for the systematic investigation of the adsorption ability of nitrogen-rich carbon nitrogen polymers on uranyl ions.
The complexation of pentavalent neptunium, Np(V), with nitrate ion in an ionic liquid solution has been studied spectroscopically for the first time. The characteristic f-f transition absorption band of Np(V) in the NIR region changes significantly upon the titration of nitrate ion into the solution, revealing strong complexation of Np(V) with nitrate ion in the ionic liquid. Most notably, the absorption band of Np(V) almost disappears when a sufficiently high concentration of nitrate ion is present in the solution. Such a rare optically "silent" species can be assigned to the 1:2 Np(V)/nitrate complex with a centrosymmetric coordination environment where Np sits at the inversion center.
While radiotherapy is a mainstay therapeutic modality for malignant tumor, the intrinsic tumor resistance to radiotherapy, as well as the concomitant radiation injury to adjacent healthy tissues, greatly limits the efficacy of cancer radiotherapy. As a result, the development of novel radioenhancers and radioprotectants is highly desired for clinical radiotherapy. In recent years, nanozymes have inspired ever-growing research interest because of their multi-enzyme activities and microenvironment-responsive feature. In view of the significant progress of nanozymes in radiation medicine, we, in this review, systematically illustrate the impressive progress of nanozymes for potentiating radiotherapy and radiation protection. First, the types of nanozymes used in tumor radiotherapy are briefly discussed. Subsequently, the main strategies of nanozymes to enhance the radiotherapy efficiency, including promoting the generation of reactive oxygen species (ROS), relieving hypoxia in tumor microenvironment and combining with other cancer therapeutic regimens, are summarized. Finally, the advances of typical nanozymes for preventing radiation-induced hematopoietic damage and gastrointestinal damage are highlighted.
A relatively new branch of science - nuclear forensics, aiming at providing the nature, origin, history and possible trafficking route of seized nuclear materials/devices, has been established and rapidly developed over decades to screen illicit nuclear activities. This highly interdisciplinary science is built upon a foundation of analytical chemistry, radiochemistry, nuclear physics, material sciences, geology, and other scientific disciplines, within which radiochemical methodologies and radioanalytical techniques play a key role. The present review provides a brief overview about the crucial aspects of nuclear forensics, including basic content, procedure, concerned elements, common separation, analytical method, and so on. The state of the art and recent progresses of nuclear forensics by research communities in China are reviewed, while selected examples and practical applications are emphasized. The challenges associated with this new area and on-going developments are highlighted and discussed.
The treatment of anionic 99TcO4- in the waste tank with high alkalinity is still very challenging. In this work, a new temperature-responsive alkaline aqueous biphasic system (ABS) based on (tri-n-butyl)-n-tetradecyl phosphonium chloride (P44414Cl) was developed to remove radioactive 99TcO4-. The phase transition mechanism was studied by cloud point titration, small-angel X-ray scattering, dynamic light scattering, and molecular dynamic simulations. As the NaOH concentration or temperature increased, the P44414+ micelle could grow and aggregate. This micelle showed a particularly high affinity toward ReO4-/99TcO4- compared to other competing anions and could directly extract more than 98.6% of 99TcO4- from simulated radioactive tank waste supernatant. Furthermore, the loaded 99TcO4- could be easily stripped by using concentrated nitric acid rather than metal salt-based reductants. This work clearly demonstrates that the alkaline ABS is a promising separation system for solving the technetium problem in the alkaline waste tank.
In this work, a technique was proposed to prepare UO2 from UO3 by the two processes of fluorination reaction of UO3 with NH4HF2 and electrochemical reduction of UO22+ for the recycle uranium. The feasibility of fluorination reaction was firstly confirmed using thermodynamic calculation; then, the products were analyzed using XRD, Raman and fluorescence to be UO2F2. The fluorination mechanism was inferred to be UO3(s) + NH4HF2 → (NH4)3UO2F5→ NH4(UO2)2F5 → UO2F2. The redox behavior of UO22+ on W electrode was investigated by cyclic voltammetry and square wave voltammetry, which indicated that UO22+ was reduced to UO2 via a two-step single electron transfer with diffusion-controlled. The diffusion coefficient of UO22+ was calculated to be 6.22 × 10−5 cm2/s. The disproportionation reaction of UO22+ was observed, and the relationship between the disproportionation reaction and scan rate was discussed. Moreover, the electrochemical fabrication of UO2 was conducted by electrolysis at −0.8 V, and the product was analyzed by XRD, SEM and EDS to be UO2. ICP-AES results showed that the extraction efficiency of UO2 could reach 98.53%.
Heavy haze events have become a serious environment and health problem in China and many developing countries, especially in big cities, like Beijing. However, the factors and processes triggered the formation of secondary particles from the gaseous pollutants are still not clear, and the processes driving evolution and degradation of heavy haze events are not well understood. Iodine isotopes (127I and 129I) as tracers were analyzed in time series aerosol samples collected from Beijing. It was observed that the 127I concentrations in aerosols peaked during the heavy haze events. The conversion of gaseous iodine to particular iodine oxides through photochemical reactions provides primary nuclei in nucleation and formation of secondary air particles, which was strengthened as the external iodine input from the fossil fuel burning in the south/southeast industrial cities and consequentially induced heavy haze events. Anthropogenic 129I concentrations peaked during clean air conditions and showed high levels in spring and later autumn compared to that in summer. 129I originated from the direct air discharges and re-emissions from contaminated seawaters by the European nuclear fuel reprocessing plants was transported to Beijing by the interaction of Westerlies and East Asian winter monsoon. Three types of mechanisms were found in the formation and evolution of heavy haze events in Beijing by the variation of 127I and 129I, i.e., iodine oxides intermediated secondary air particles, dust storm and mixed mode by both secondary air particles and dust storm induced processes.
The development of uranyl ion detection technology has exhibited its significance in public security and environmental fields for the radioactivity and chemical toxicity of uranyl ion. The WHO standard of uranyl ion makes it necessary to develop highly sensitive uranyl rapid warning system in drinking water monitoring. Herein, a visualized rapid warning system for trace uranyl ion is carried out based on electrochemiluminescence (ECL) imaging technology to give an ultra-low limit of detection (LOD) and high selectivity. Amidoxime, a bi-functional group with both uranyl ion capturing and co-reactive functions, is modified on a conjugated polymer backbone with strong ECL signal to be prepared into three-in-one polymer nanoparticles (PNPs) with self-enhanced ECL property. The captured uranyl ion can enhance the ECL signal of PNPs via resonance energy transfer process to give the LOD as 0.5 ng/L, which is much lower than the known luminescent uranyl sensors. Furthermore, ECL imaging technology is introduced into realizing visualized uranyl rapid warning, and can be successfully applied on natural water samples. This study provides a novel strategy for uranyl rapid warning, and shows its potential meaning in public security and environmental fields.
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